Book excerpt: Measurements were made of sound speed and attenuation in marine sediments at 15, 30, and 60kHz by means of in situ acoustic probe instrumentation in conjunction with CURV II. These experiments were conducted in silty sand and sandy silt Continental Shelf areas of the Santa Barbara Channel, California. The main conclusions are: (1) attenuation was found to be about 3, 10, and 20 dB per meter at 15, 30, and 60 kHz, respectively; (2) for the attenuation equation, alpha = K(f to the nth power) (where alpha is sound attenuation in dB per meter, K is a dimensional material parameter, and f is frequency in kHz), the exponent, n, was found to be about 1.2, and K varied from approximately 0.1 to 0.2; (3) no significant sound-speed dispersion was found, in agreement with many other investigations; and (4) individual acoustic measurements made in close proximity to one another in a nominally homogeneous bottom can vary appreciably, although their average values may be in close agreement. (Author).